Apparatus for reducing hydrogen concentration in exhaust gas of an exhaust system for a fuel cell vehicle

ABSTRACT

An apparatus for reducing hydrogen concentration in exhaust gas of an exhaust system of a fuel cell vehicle includes a bumper cover disposed at a rear portion of the fuel cell vehicle, the bumper cover forming a streamlined exterior surface, and an exhaust gas guiding unit interconnecting the exhaust system and the bumper cover, the exhaust gas guiding unit guiding the exhaust gas to the streamlined exterior surface of the bumper cover.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.15/640,723 entitled “APPARATUS FOR REDUCING HYDROGEN CONCENTRATION INEXHAUST GAS OF AN EXHAUST SYSTEM FOR A FUEL CELL VEHICLE”, filed Jul. 3,2017, which claims priority to and the benefit of Korean PatentApplication No. 10-2016-0165280 filed in the Korean IntellectualProperty Office on Dec. 6, 2016. The entire contents of these priorfiled applications are incorporated herein by reference.

BACKGROUND Field of the Disclosure

The present disclosure relates to an apparatus for reducing hydrogenconcentration in exhaust gas of an exhaust system of a fuel cellvehicle.

Description of the Related Art

In general, a fuel cell system is a kind of a power generating systemthat supplies air and hydrogen to a fuel cell to generate electricalenergy by an electrochemical reaction between hydrogen and oxygen by thefuel cell. For example, the fuel cell system is used to drive a drivingsource such as an electric motor in a vehicle, a ship, a train, or aplane.

The fuel cell system includes a stack in which fuel cells are stacked, ahydrogen supply unit that supplies hydrogen to fuel electrodes of thefuel cells, an air supply unit that supplies air to air electrodes ofthe fuel cells, and a heat/water management unit that controls anoperating temperature of the stack by removing heat and water resultingfrom fuel cell reaction.

Meanwhile, in the case of a polymer fuel cell, an appropriate amount ofmoisture allows an ion exchange membrane of a membrane-electrodeassembly (MEA) to smoothly operate. To this end, the air supply deviceof the fuel cell system includes a humidification device for humidifiedair supplied to the fuel cell.

For example, the humidification device humidifies dried air suppliedthrough an air compressor of the air supply device using moisture inhigh temperature and high humidity air exhausted from the cathode of thefuel cell, and supplies the humidified air to the cathode of the fuelcell.

Further, the fuel cell system includes a hydrogen re-circulating unitthat mixes hydrogen discharged from the fuel electrodes of the fuelcells with hydrogen supplied from the hydrogen supply unit to supply themixture to the fuel electrodes.

Meanwhile, impurities such as nitrogen and water vapor are accumulatedto decrease a concentration of hydrogen in the fuel electrodes of thefuel cells during an operation of the fuel cell system, and when theconcentration of the hydrogen is excessively decreased, cell omissionmay occur in the fuel cell stack.

In order to address this problem, in the fuel cell system, a purge valveis provided on the hydrogen discharge side of the fuel cell stack. Byperiodically opening the purge valve, the impurities and the hydrogenare discharged. The hydrogen concentration of the fuel electrodes isthus maintained at more than a certain level.

When the purge valve is opened to purge the fuel electrodes, the fuelelectrodes discharge the impurities and the hydrogen, and the purge gasis introduced into the humidifying device together with the airdischarged from the fuel cell stack.

Thereafter, water vapor in the impurities is used as a humidifyingsource of the reactant gas for the electrochemical reaction of the fuelcell in the humidifying device, and gases such as hydrogen and nitrogenare discharged into the atmosphere through an exhaust line of thehumidifying device.

Accordingly, such a hydrogen purge method is a technique for obtaining adilution effect of purge hydrogen by mixing hydrogen discharged from thefuel electrode with air discharged through the air discharge line fromthe fuel cell stack.

While starting and stopping of the fuel cell system or in an idlecondition (for example, an Idle, Stop, and Go (ISG) condition of thefuel cell vehicle) of a fuel cell vehicle employing the fuel cellsystem, a substantive amount of hydrogen that crosses over from the fuelelectrode to the air electrode through a membrane may be exhausted.

In this case, the hydrogen together with the air is exhausted from theair electrode of the fuel cells to a humidifying device, diluted by airat the humidifier, and then exhausted to an atmosphere with reducedconcentration.

However, according to the conventional scheme, although the hydrogenexhausted from the fuel cell system is mixed in the humidifier with airexhausted from the air electrode so as to reduce the hydrogenconcentration, it is difficult to realize a sufficient mixing effect andthe hydrogen concentration may not be sufficiently reduced.

Therefore, hydrogen concentration exhausted from the fuel cell systemmay not be effectively reduced, and highly dense hydrogen may beexhausted depending on the driving condition of the fuel cell system,which implies a possibility of ignition and explosion of the exhaustgas.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the disclosure.Therefore the Background section may contain information that does notconstitute prior art.

SUMMARY OF THE DISCLOSURE

The present disclosure provides an apparatus for reducing hydrogenconcentration in exhaust gas of an exhaust system of a fuel cellvehicle. The apparatus may be useful for effectively reducing thehydrogen concentration of exhaust gas of a fuel cell system of a fuelcell vehicle.

An apparatus for reducing hydrogen concentration in exhaust gas of anexhaust system of a fuel cell vehicle according to an embodiment mayinclude a bumper cover and an exhaust gas guiding unit. The bumper covermay be disposed at a rear portion of the fuel cell vehicle, and thebumper cover forms a streamlined exterior surface. The exhaust gasguiding unit may interconnect the exhaust system and the bumper coverand guide the exhaust gas to the streamlined exterior surface of thebumper cover.

While the exhaust gas may be guided to the streamlined exterior surfaceof the bumper cover, hydrogen in the exhaust gas may flow along thestreamlined exterior surface of the bumper cover, thereby being diffusedto, and diluted by, an exterior air.

The exhaust gas guiding unit may include an extension portion formed byextending an exhaust end of the exhaust system and connected with abottom of the bumper cover.

An apparatus for reducing hydrogen concentration in exhaust gas of anexhaust system of a fuel cell vehicle according to another embodimentmay include a bumper cover and an air amplifier. The bumper cover may bedisposed at a rear portion of a vehicle, forming a closed spaceconnected with an exhaust end of the exhaust system, and forming astreamlined exterior surface where the close space may be connected witha rear of the bumper cover by a gap formed along a length direction ofthe bumper cover. The air amplifier may exhaust the exhaust gas to thestreamlined exterior surface through the gap and guiding an exterior airto the streamlined exterior surface.

The air amplifier may guide the exhaust gas to stick to, and flow along,the streamlined exterior surface of the bumper cover. As a result,hydrogen in the exhaust gas is diffused to, and diluted by, the exteriorair.

The bumper cover may be formed in a shape of a hollow loop incross-section. The streamlined curved surface may be formed as a rearsurface of the bumper cover. The rear surface may be overlapped by afront surface with the gap at a bottom of the bumper cover.

A blocking protrusion may be formed at a top of the bumper cover so asto block hydrogen contained in the exhaust gas from flowing upward.

An apparatus for reducing hydrogen concentration in exhaust gas of anexhaust system of a fuel cell vehicle according to yet anotherembodiment may include a collecting member, at least one passage member,and an exhaust portion. The collecting member may be installed at aninterior of a bumper cover disposed at a rear portion of the fuel cellvehicle and collect the exhaust gas exhausted from the exhaust system.

The at least one passage member may be disposed in a length direction ofthe bumper cover at the interior of the bumper cover and be connectedwith the collecting member so as to allow the collected gas to flowalong the length direction. The exhaust portion may be connected withthe at least one passage member, formed along the length direction ofthe bumper cover, exhaust the exhaust gas inside the at least onepassage member, and guide the exhausted gas toward the streamlinedexterior surface of the bumper cover.

The collecting member may be fixed to the bumper cover at an interior ofthe bumper cover. The at least one passage member may be fixed to thebumper cover at the interior of the bumper cover.

The collecting member may be formed as a housing that includes a firstport connected with the exhaust system, a second port connected with theat least one passage member, and a third port for draining moisturecontained in the collected exhaust gas.

A water trap valve for selectively opening/closing the third port may beprovided at the third port.

The exhaust portion may include an exhaust slit formed along the lengthdirection of the bumper cover.

Each of the at least one passage member may be provided with aconnection slit formed along the length direction of the bumper cover,where the connection slit may be connected with the exhaust slit.

The exhaust slit may be located upward and rearward with respect to theconnection slit, such that the exhaust gas may move upward and rearwardwhile flowing from the connection slit to the exhaust slit.

The connection slit and the exhaust slit may be interconnected by aconnection passage.

The exhaust portion may include a plurality of exhaust holes formed witha predetermined spacing along the length direction of the bumper cover.

Each of the at least one passage member may be provided with a pluralityof connection holes that are formed in the length direction andrespectively connected with the plurality of exhaust holes.

The plurality of exhaust holes may be located upward and rearward withrespect to the plurality of connection holes, such that the exhaust gasmay move upward and rearward while flowing from the plurality ofconnection holes to the plurality of exhaust holes.

The plurality of connection holes and the plurality of exhaust holes maybe interconnected by a plurality of connection passages.

An apparatus for reducing hydrogen concentration in exhaust gas of anexhaust system of a fuel cell vehicle according to yet anotherembodiment may include a collecting member and an exhaust portion. Thecollecting member may be installed at an interior of a bumper coverdisposed at a rear portion of the fuel cell vehicle, collect exhaust gasexhausted from the exhaust system, and exhaust the collected exhaust gasto the interior of the bumper cover. The bumper cover may form astreamlined exterior surface. The exhaust portion may include a meshscreen formed at the bumper cover, discharge exhaust gas at the interiorof the bumper cover to an exterior of the bumper cover, and guide thedischarged gas to the streamlined exterior surface of the bumper cover.

According to disclosed embodiments, exhaust gas containing hydrogen andair is guided to a streamlined exterior surface of a rear bumper cover,and diffused to and diluted by an exterior air.

Thus, by utilizing the bumper at a rear portion of a fuel cell vehiclein order to reduce hydrogen concentration in the exhaust gas by dilutingthe exhaust gas by an exterior air, hydrogen concentration in theexhaust gas may be effectively reduced.

Further effects that can be obtained or expected from the disclosedembodiments are directly or suggestively described in the followingdetailed description. That is, various effects expected from thedisclosed embodiments will be described in the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a fuel cell system in which an apparatus inaccordance with the disclosed embodiments is applied.

FIG. 2 is a schematic view of an apparatus for reducing hydrogenconcentration in exhaust gas of an exhaust system of a fuel cell vehicleaccording to a first disclosed embodiment.

FIG. 3A and FIG. 3B are a schematic views of an apparatus for reducinghydrogen concentration in exhaust gas of an exhaust system of a fuelcell vehicle according to a second disclosed embodiment.

FIG. 4 is a schematic view of an apparatus for reducing hydrogenconcentration in exhaust gas of an exhaust system of a fuel cell vehicleaccording to a third disclosed embodiment.

FIG. 5 is a perspective view of an example of an apparatus for reducinghydrogen concentration in exhaust gas of an exhaust system of a fuelcell vehicle according to a third disclosed embodiment.

FIG. 6 is a perspective view of another example of an apparatus forreducing hydrogen concentration in exhaust gas of an exhaust system of afuel cell vehicle according to a third disclosed embodiment.

FIG. 7 is a perspective view of a yet another example of an apparatusfor reducing hydrogen concentration in exhaust gas of an exhaust systemof a fuel cell vehicle according to a third disclosed embodiment.

FIG. 8 is a schematic view of an apparatus for reducing hydrogenconcentration in exhaust gas of an exhaust system of a fuel cell vehicleaccording to a fourth disclosed embodiment.

The following reference symbols are used throughout the drawings and thefollowing Detailed Description section:

1: fuel cell system 2: fuel cell stack 2a: air electrode 2b: fuelelectrode 2c: fuel cell 3: air supply unit 4: hydrogen supply unit 5:humidifier 6: hydrogen recirculation unit 7: heat/water management unit8: purge valve 9: exhaust system 9a: exhaust line 9b: exhaust end 101:bumper 103, 203, 303, 403: bumper cover 110, 210, 310, 410: exhaust gasguiding unit 111: extension portion 201: closed space 205: front surface207, 307, 407: rear surface 209: blocking protrusion 211: air amplifier213: gap 311, 411: collecting member 313: first port 315: second port317: third port 321: water trap valve 331: passage member 333:connection slit 333a: connection hole 351, 451: exhaust portion 353:exhaust slit 353a: exhaust hole 371: connection passage 413: intake port490: mesh screen

DETAILED DESCRIPTION

The present disclosure will be described more fully hereinafter withreference to the accompanying drawings, in which disclosed embodimentsare shown. As those skilled in the art would realize, the describedembodiments may be modified in various different ways, all withoutdeparting from the spirit or scope of the present disclosure.

The drawings and description are to be regarded as illustrative innature and not restrictive, and like reference numerals designate likeelements throughout the specification.

The size and the thickness of each component illustrated in the drawingsare arbitrarily illustrated in the drawings for better understanding andease of description, but the present disclosure is not limited to theillustration. In the drawings, the thicknesses of various portions andregions are enlarged for clarity.

In the following description, dividing names of components into first,second and the like is to divide the names because the names of thecomponents are the same as each other and an order thereof is notparticularly limited.

In addition, unless explicitly described to the contrary, the word“comprise” and variations such as “comprises” or “comprising”, will beunderstood to imply the inclusion of stated elements but not theexclusion of any other elements.

In addition, the terms “˜unit”, “˜means”, “˜part”, and “member”described in the specification mean units of a comprehensiveconfiguration for performing at least one function and operation.

FIG. 1 is a block diagram of a fuel cell system in which an apparatus inaccordance with disclosed embodiments is applied.

Referring to FIG. 1, a fuel cell system 1 applied with the disclosedembodiments is an electricity generator system generating electricalenergy by an electrochemical reaction of fuel and an oxidizer, and maybe installed in a fuel cell vehicle that drives an electric motor byelectrical energy.

In the disclosed embodiments, fuel used in the fuel cell system 1 iscalled hydrogen gas (hereinafter, called “hydrogen” for convenience),and an oxidizer used in the fuel cell system 1 is called air.

Such a fuel cell system 1 includes a fuel cell stack 2, an air supplyunit 3, a hydrogen supply unit 4, a humidifier 5, a hydrogenrecirculation unit 6, and a heat/water management unit 7.

The fuel cell stack 2 is an accumulated assembly of fuel cells 2 c,respectively including a membrane (not shown), an air electrode 2 a, anda fuel electrode 2 b. The fuel cells 2 c are supplied with hydrogen bythe fuel electrode 2 b and air by the air electrode 2 a, and generateselectrical energy by an electrochemical reaction of hydrogen and oxygen.

The air supply unit 3 is driven by electricity and supplies atmosphericair to the air electrode 2 a of the fuel cells 2 c. The air supply unit3 may include an air compressor or an air blower. The hydrogen supplyunit 4 stores compressed hydrogen and may include a hydrogen tank forsupplying the compressed hydrogen to the fuel electrode 2 b of the fuelcells 2 c.

The humidifier 5 may include a membrane humidifier that humidifies airsupplied from the air supply unit 3 by using an exhaust air containingmoisture and exhausted from the air electrode 2 a of the fuel cells 2 c,and supplies the humidified air to the air electrode 2 a.

The hydrogen recirculation unit 6 recirculates hydrogen exhausted fromthe fuel electrode 2 b of the fuel cells 2 c to the fuel electrode 2 b.The hydrogen recirculation unit 6 may mix the hydrogen exhausted fromthe fuel electrode 2 b and the hydrogen supplied from the hydrogensupply unit 4 and supply the mixed hydrogen to the fuel electrode 2 b.

The heat/water management unit 7 eliminates heat and water formed by theelectrochemical reaction of the fuel cells 2 c, and thereby controls anoperating temperature of the fuel cell stack 2.

The above constituent elements of such a fuel cell system 1 may beformed as known in the art.

When a fuel cell vehicle installed with the fuel cell system is beingstarted, the fuel cell system 1 exhausts hydrogen by a cross-overtogether with air from the air electrode 2 a of the fuel cells 2 c, andexhausts purge hydrogen from the fuel electrode 2 b of the fuel cells 2c.

In addition, the fuel cell system 1 exhausts only purge hydrogen fromthe fuel electrode 2 b of the fuel cells 2 c during a driving of thevehicle. When the vehicle is stopped or in an idle state (for example,in the case of an Idle, Stop, and Go (ISG) condition), the fuel cellsystem 1 exhausts hydrogen by a cross-over together with air from theair electrode 2 a of the fuel cells 2 c.

The cross-over hydrogen means hydrogen that crosses over from the fuelelectrode 2 b of the fuel cells 2 c to the air electrode 2 a through themembrane by a residual pressure.

The purge hydrogen means hydrogen exhausted from the fuel electrode 2 btogether with impurities by an operation of the purge valve 8, so as toremove impurities such as nitrogen and water vapor accumulated in thefuel electrode 2 b of the fuel cells 2 c.

The hydrogen exhausted from the fuel cells 2 c may be supplied to thehumidifier 5, and exhausted from the humidifier 5 together with air.Therefore, hydrogen concentration may be reduced in the exhaust gas dueto dilution by air.

That is, when the vehicle is being started, driven, and stopped or in anidle state, the hydrogen exhausted from the fuel cells 2 c inflows tothe humidifier 5 together with the air exhausted from the fuel cells 2c, and hydrogen concentration is reduced by the air.

The fuel cell system 1 includes an exhaust system 9 so as to exhaust thegas (a gas containing hydrogen and air; hereinafter called an “exhaustgas”) exhausted from the humidifier 5 to an atmosphere. Here, theexhaust gas contains water and water vapor as well as hydrogen and air.

The exhaust system 9 may include an exhaust line 9 a arranged at abottom of the vehicle from a front to a rear of the vehicle. The exhaustline 9 a guides the exhaust gas from the front to the rear of thevehicle, and emits the exhaust gas to the atmosphere.

The exhaust line 9 a may be formed as a pipe, and various parts, such asa muffler to reduce an exhaust noise, a sensor to detect a hydrogenconcentration, may be installed in the exhaust line 9 a.

When the vehicle is being started and stopped or in the idle state, theexhaust gas is exhausted from the exhaust system 9 at a low flow rate,which is a low flow rate and low pressure condition of the exhaust gas,and in this case, the exhaust gas contains hydrogen with relatively highconcentration.

When the vehicle is driven, the exhaust gas is exhausted from theexhaust system 9 at a high flow rate, which is a high flow rate and highpressure condition of the exhaust gas, and in this case, the exhaust gascontains hydrogen with relatively low concentration.

Here, low flow rate/low pressure condition and high flow rate/highpressure condition of the exhaust gas may be determined by a consumedpower by the air compressor or air blower of air supply unit 3.

In the disclosed embodiments, the above-described low flow rate/lowpressure condition and high flow rate/high pressure condition may beclearly identified depending vehicle state (staring, driving, stopping,idle state), and thus the low flow rate/low pressure condition and thehigh flow rate/high pressure condition may not be limited to a specificvalue or range.

An apparatus 100 for reducing hydrogen concentration for an exhaustsystem of a fuel cell vehicle may be connected with an exhaust system 9at a rear of the fuel cell vehicle.

By forming the apparatus 100 for reducing hydrogen concentration for anexhaust system of a fuel cell vehicle at the rear of the fuel cellvehicle, condensate water containing moisture in the exhaust gas may beexhausted rearward, and thus the condensate water may not be frozen inthe course of the exhaust line.

By forming the apparatus 100 for reducing hydrogen concentration to beconnected with the exhaust system 9 at the rear of the vehicle, thehydrogen contained in the exhaust gas may be maximally diluted byexterior air.

According to an apparatus 100 for reducing hydrogen concentration for anexhaust system of a fuel cell vehicle according to the disclosedembodiments, the hydrogen in the exhaust gas exhausted through theexhaust system 9 is diffused to, and diluted by, the exterior air, andthereby the hydrogen concentration may be effectively reduced.

Hereinafter, a surface toward a front of the fuel cell vehicle is calleda front surface, and a surface toward a rear of the fuel cell vehicle iscalled a rear surface. In addition, “end” may be interpreted as aliteral end or an area/section/region/portion that includes the literalend.

According to disclosed embodiments that are hereinafter described, theexhaust gas exhausted through the exhaust system 9 is guided toward abumper at a rear portion of a vehicle and the hydrogen contained in theexhaust gas is diffused to, and diluted by, exterior air. In thisregard, the bumper may be construed as a component of an exhaust system.

According to an apparatus 100 (200, 300, 400) for reducing hydrogenconcentration for an exhaust system of a fuel cell vehicle according tothe disclosed embodiments, the exhaust system 9 and the bumper at a rearportion of a vehicle 101 are connected. In addition, the apparatus 100(200, 300, 400) may include an exhaust gas guiding unit 110 (210, 310,410) to guide the exhaust gas exhausted through the exhaust system 9toward a streamlined exterior surface of the bumper 101.

FIG. 2 is a schematic view of an apparatus for reducing hydrogenconcentration in exhaust gas of an exhaust system of a fuel cell vehicleaccording to a first disclosed embodiment.

Referring to FIG. 1 and FIG. 2, an apparatus 100 for reducing hydrogenconcentration for an exhaust system of a fuel cell vehicle according toa first disclosed embodiment includes an exhaust gas guiding unit 110that guides the exhaust gas containing hydrogen along a streamlinedexterior surface of the bumper cover 103 and diffuses the hydrogen tothe exterior air to be diluted by the exterior air.

The bumper cover 103 is arranged at the bumper 101 at a rear portion ofa fuel cell vehicle, where, for example, a front side of the bumpercover 103 is open and a rear surface forms a streamlined exteriorsurface upward. That is, the rear surface of the bumper cover 103 formsa curved surface in a vertical direction.

The exhaust gas guiding unit 110 includes an extension portion 111 thatis formed by extending the exhaust end 9 b of the exhaust system 9toward a bottom of the bumper cover 103.

The extension portion 111 is provided at the rear end of the exhaustline 9 a that is below the bumper 101 at a rear of the fuel cellvehicle, and extends the exhaust end 9 b illustrated by a single-dotchain line to the bottom of the bumper cover 103.

Thus, the extension portion 111 connects the exhaust end 9 b with thebottom of the bumper cover 103. By such a configuration, a diameter ofthe exhaust line 9 a becomes larger as the exhaust line 9 a goesrearward.

Because the extension portion 111 extending the exhaust end 9 b of theexhaust system 9 to the bottom of the bumper cover 103 is formed at therear end of the exhaust line 9 a, the hydrogen contained in the exhaustgas exhausted by the exhaust end 9 b may flow upward along thestreamlined exterior surface of the bumper cover 103. Such a flow isenabled by a Coanda effect in which a stream close to a wall sticks tothe wall.

The hydrogen exhausted together with the air through the exhaust line 9a of the exhaust system 9, being lighter than the air, flows upwardalong the streamlined exterior surface of the bumper cover 103 by theCoanda effect. The air and water are exhausted to an atmosphere throughthe exhaust end 9 b.

Thus, according to a disclosed embodiment, the hydrogen contained in theexhaust gas exhausted by the exhaust end 9 b of the exhaust system 9flows upward along the streamlined exterior surface of the bumper cover103, and therefore, the hydrogen is diffused to, and diluted by, ambientair (exterior air).

Therefore, hydrogen concentration in the exhaust gas exhausted to theatmosphere through the exhaust system 9 may be effectively reduced.

FIG. 3A and FIG. 3B are schematic views of an apparatus for reducinghydrogen concentration in exhaust gas of an exhaust system of a fuelcell vehicle according to a second disclosed embodiment.

Referring to FIG. 3A and FIG. 3B, an apparatus 200 for reducing hydrogenconcentration for an exhaust system of a fuel cell vehicle according toa second disclosed embodiment includes a closed space 201 and a bumpercover 203. The closed space 201 is connected with the exhaust end 9 b ofthe exhaust system 9. The bumper cover 203 has a streamlined exteriorsurface at a rear portion of a vehicle.

The present disclosed embodiment is provided with an air amplifier 211for accelerating exterior air toward the streamlined exterior surface ofthe bumper cover 203.

The bumper cover 203 has a shape of a hollow round loop forming theclosed space 201 as an interior space, and includes a front surface 205formed as a flat surface and a rear surface 207 formed as thestreamlined curved surface.

A side surface (not shown) of the bumper cover 203 opposite to a sideconnected to the exhaust end 9 b is closed. A bottom of the bumper cover203 where the streamlined curved surface (i.e., the rear surface 207)meets the front surface 205 has a roundish form. The exhaust end 9 a ofthe exhaust system 9 is connected with a side (shown in the left) of thebumper cover 203, and the exhaust gas flows from the exhaust system 9 tothe closed space 201 of the bumper cover 203.

The air amplifier 211 is formed at the bottom of bumper cover 203 alonga length direction of the bumper cover 203. The air amplifier 211 formsa gap 213 along the length direction of the bumper cover 203 between thefront surface 205 and the rear surface 207 of the streamlined curvedsurface. That is, the front surface 205 partially overlaps the rearsurface 207 with the gap 213, and this overlapping portion forms the airamplifier 211.

While the exhaust gas flows from the exhaust system 9 into the closedspace 201 of the bumper cover 203, the air amplifier 211 exhausts theinflowing exhaust gas to the streamlined exterior surface of the rearsurface 207 through the gap 213, and also guides exterior air to thestreamlined exterior surface.

The air amplifier 211 enables the exhaust gas emitted through the gap213 to flow along the streamlined exterior surface of the rear surface207, and thus hydrogen in the emitted gas is diffused to, and dilutedby, the exterior air.

A blocking protrusion 209 is formed at a top of the bumper cover 203, soas to block the hydrogen flowing upward along the streamlined exteriorsurface of the rear surface 207, such that the hydrogen may not reach atrunk space (not shown).

The blocking protrusion 209 is integrally formed at the top of thebumper cover 203 along the length direction of the bumper cover 203, andis formed to be slanted downward to the rear of the bumper cover 203.Thus, the blocking protrusion 209 may block the hydrogen in the exhaustgas flowing along the streamlined exterior surface of the rear surface207 and guide the hydrogen in the exhaust gas downward.

According to an apparatus 200 for reducing hydrogen concentration for anexhaust system of a fuel cell vehicle according to a second disclosedembodiment, the exhaust gas exhausted through the exhaust system 9 firstflows in the closed space 201 of the bumper cover 203.

When the exhaust gas is emitted through the gap 213, a flow speed of theemitted exhaust gas is accelerated due to the round shape of the bulgyrear surface 207.

The acceleration of flow speed of the emitted gas inhales the exhaustgas from the closed space 201, and consequently, the exhaust gas isemitted from the closed space 201 through the gap 213 of the airamplifier 211 at a very high speed. The exhaust gas emitted through thegap 213 sticks to, and flows upward along, the streamlined exteriorsurface of the rear surface 207 by the Coanda effect. By emitting theexhaust gas at a high speed, a pressure at a rear of the streamlinedcurved surface of the rear surface 207 becomes lowered. Therefore, theair in vicinity of the rear surface 207 of the streamlined curvedsurface is inhaled toward the curved surface, and thereby a very strongstream is formed in an upward direction along the curved surface.

Such an air amplifier action to form the strong stream is apparent to aperson of ordinary skill in the art, in view of the above-describedarrangement of the present embodiment.

Thus, according to the present embodiment, the exhaust gas flowing intothe bumper cover 203 is emitted through the gap 213 of the air amplifier211 and flows upward along the streamlined exterior surface of the rearsurface 207. At the same time, ambient air (exterior air) is guidedalong the streamlined exterior surface of the rear surface 207 by astrong stream.

As a result, the hydrogen in the exhaust gas emitted through the gap 213of the air amplifier 211 is diffused to, and diluted by, the exteriorair.

Meanwhile, while the exhaust gas flows upward along the streamlinedexterior surface of the rear surface 207 and the hydrogen in the exhaustgas is diluted, the blocking protrusion 209 at the top of the bumpercover 203 blocks the exhaust gas to flow further upward, e.g., to flowinto a trunk space (not shown). Then, the exhaust gas blocked by theblocking protrusion 209 flows into the atmosphere in a downwarddirection.

FIG. 4 is a schematic view of an apparatus for reducing hydrogenconcentration in exhaust gas of an exhaust system of a fuel cell vehicleaccording to a third disclosed embodiment.

Referring to FIG. 4, an apparatus 300 for reducing hydrogenconcentration for an exhaust system of a fuel cell vehicle according toa third disclosed embodiment is provided with an exhaust gas guidingunit 310. The exhaust gas guiding unit 310 receives the exhaust gasexhausted from the exhaust system 9 inside an interior space of thebumper cover 303, and guides the exhaust gas toward the streamlinedexterior surface of the rear surface 307 of the bumper cover 303. Theexhaust gas guiding unit 310 includes a collecting member 311, a passagemember 331, and an exhaust portion 351.

The bumper cover 303 has an open front side and a closed rear surface307. The rear surface 307 forms a streamlined exterior surface (curvedsurface).

In the present embodiment, the collecting member 311 collects theexhaust gas exhausted through the exhaust system 9. The collectingmember 311 is provided at an interior of the bumper cover 303, and fixedto the bumper cover 303.

The collecting member 311 is in the form of a closed housing, e.g., in ashape of a rectangular parallelepiped, although FIG. 5 and FIG. 6illustrate the collecting member 311 to be open for the purpose ofbetter understanding and illustration. Such a collecting member 311includes a first port 313 connected with the exhaust system 9, a secondport 315 connected with the passage member 331, and a third port 317 fordraining moisture (water) contained in the exhaust gas.

The third port 317 is formed at a bottom surface of the collectingmember 311, and a water trap valve 321 is installed at the third port317 so as to open and close the third port 317 by an electrical signal.

When the third port 317 is closed by the water trap valve 321, moistureor water in the exhaust gas is collected inside the collecting member311. When the third port 317 is opened by the water trap valve 321, thecollected water in the collecting member 311 is drained through thethird port 317.

In the present embodiment, the passage member 331 is formed along thelength direction of the bumper cover 303 at an interior of the bumpercover 303, and is connected with the second port 315 of the collectingmember 311. The passage member 331 allows the exhaust gas in thecollecting member 311 to flow in a length direction of bumper cover 303,and one end of the passage member 331 is fixed to the bumper cover 303.

The passage member 331 is provided with a connection slit 333 formedalong the length direction of the bumper cover 303, in order forexteriorly exhausting the exhaust gas. The connection slit 333 isconnected with the exhaust portion 351.

As an example of an apparatus 300 for reducing hydrogen concentrationfor an exhaust system of a fuel cell vehicle according to a thirddisclosed embodiment, a single passage member 331 may be provided at theinterior of the bumper cover 303, as shown in FIG. 4 and FIG. 5.

As another example of an apparatus 300 for reducing hydrogenconcentration for an exhaust system of a fuel cell vehicle according toa third disclosed embodiment, a plurality of passage members 331 (e.g.,three passage members 331) may be provided at the interior of the bumpercover 303, as shown in FIG. 6.

By employing the plurality of passage members 331 as shown in FIG. 6, apressure difference for exhausting the exhaust gas from the exhaustsystem 9 to the passage member 331 through the collecting member 311 maybe reduced, and noise caused by the flow of the exhaust gas may also bereduced.

As shown in FIG. 4 to FIG. 6, in the present embodiment, the exhaustportion 351 exhausts the exhaust gas through the connection slit 333 ofthe passage member 331 to an exterior of the rear surface 307 of thebumper cover 303.

The exhaust portion 351 includes an exhaust slit 353 connected with theconnection slit 333 of the passage member 331. The exhaust slit 353 isformed at the rear surface 307 of the bumper cover 303 along the lengthdirection thereof.

The exhaust slit 353 of the exhaust portion 351 is located upward andrearward with respect to the connection slit 333 of the passage member331, and the exhaust slit 353 and the connection slit 333 areinterconnected by the connection passage 371.

By connecting the connection slit 333 and the exhaust slit 353 in aslope by the connection passage 371, the exhaust gas exhausted throughthe exhaust slit 353 through the connection slit 333 and the connectionpassage 371 may easily flow upward along the streamlined exteriorsurface of the rear surface 307 of the bumper cover 303.

According to an apparatus 300 for reducing hydrogen concentration for anexhaust system of a fuel cell vehicle according to a third disclosedembodiment, the exhaust gas exhausted through the exhaust system 9 firstflows into the collecting member 311 through the first port 313 of thecollecting member 311.

Then, the exhaust gas flows into the passage member 331 through thesecond port 315 of the collecting member 311, and after flowing throughthe passage member 331, is exhausted to the exhaust slit 353 of theexhaust portion 351 through the connection slit 333 and the connectionpassage 371. Subsequently, the exhaust gas is exhausted to an exteriorof the rear surface 307 of the bumper cover 303 through the exhaust slit353.

Since the connection slit 333 and the exhaust slit 353 is interconnectedby the connection passage 371 in a slope in the present embodiment, theexhaust gas exhausted from the exhaust slit 353 may be easily guided tothe streamlined exterior surface of the rear surface 307 of the bumpercover 303.

As described above, the exhaust gas exhausted through the exhaust slit353 of the exhaust portion 351 is guided to the streamlined exteriorsurface of the rear surface 307 of the bumper cover 303, andaccordingly, the exhaust gas sticks to, and flows upward along, thestreamlined exterior surface of the rear surface 307 by the Coandaeffect.

In the present embodiment as described above, the exhaust gas flowsupward along the streamlined exterior surface of the rear surface 307 ofthe bumper cover 303, and the hydrogen in the exhaust gas may bediffused to, and diluted by, the ambient air (exterior air).

In the present embodiment, moisture in the exhaust gas flowing into thecollecting member 311 may be collected by closing the third port 317 ofthe collecting member 311 by the water trap valve 321.

In the present embodiment, water collected in the collecting member 311may be drained through the third port 317 by opening the third port 317of the collecting member 311 by the water trap valve 321.

As a yet another example of an apparatus 300 for reducing hydrogenconcentration for an exhaust system of a fuel cell vehicle according toa third disclosed embodiment, a plurality of connection holes 333 a witha predetermined spacing may be formed along the length direction of thebumper cover 303, as the passage member 331 as shown in FIG. 7.

As the exhaust portion 351, a plurality of exhaust holes 353 a may beformed along the length direction of the rear surface 307 of the bumpercover 303. The plurality of exhaust holes 353 a may be formed apart by apredetermined spacing and connected with the connection holes 333 a ofthe passage member 331.

The exhaust holes 353 a are located upward and rearward with respect tothe connection holes 333 a, and are connected with the connection holes333 a by the connection passages 371 (refer to FIG. 4).

FIG. 8 is a schematic view of an apparatus for reducing hydrogenconcentration in exhaust gas of an exhaust system of a fuel cell vehicleaccording to a fourth disclosed embodiment.

Referring to FIG. 8, an apparatus 400 for reducing hydrogenconcentration for an exhaust system of a fuel cell vehicle according toa disclosed embodiment may include a exhaust gas guiding unit 410including a collecting member 411 and a mesh type exhaust portion 451.The collecting member 411 is installed at an interior of the bumpercover 403, and the mesh type exhaust portion 451 is formed at a rearsurface 407 of the bumper cover 403.

The collecting member 411 collects the exhaust gas exhausted from theexhaust system 9, and exhausts the exhaust gas toward an interior of thebumper cover 403.

The collecting member 411 is formed with an intake port 413 throughwhich the exhaust gas exhausted from the exhaust system 9 flow into thecollecting member 411. In addition, the collecting member 411 has anopen face toward an interior of the bumper cover 403 such that theexhaust gas may be exhausted toward the interior of the bumper cover403.

In the present embodiment, the exhaust portion 451 exhausts the exhaustgas exhausted to the interior of the bumper cover 403 through thecollecting member 411 toward an exterior of the rear surface 407 of thebumper cover 403 and guides the exhaust gas to the streamlined exteriorsurface of the rear surface 407. The exhaust portion 451 may be realizedas a mesh screen 490 formed at the rear surface 407 of the bumper cover403.

According to an apparatus 400 for reducing hydrogen concentration for anexhaust system of a fuel cell vehicle according to a fourth disclosedembodiment, the exhaust gas exhausted from the exhaust system 9 iscollected in the collecting member 411, and the collected exhaust gas isexhausted toward the interior of the bumper cover 403 through the openface of the collecting member 411.

Then, the exhaust gas is exhausted from the interior to the exterior ofthe rear surface 407 of the bumper cover 403 through the exhaust portion451, and guided to the streamlined exterior surface of the rear surface407. Then the exhausted gas sticks to and flows upward along thestreamlined exterior surface of the rear surface 407 by the Coandaeffect.

In the present embodiment as described above, the exhaust gas isexhausted to an exterior of the rear surface 407 of the bumper cover 403through the mesh type exhaust portion 451, and flows upward along thestreamlined exterior surface of the rear surface 407. Therefore, thehydrogen in the exhaust gas may be diffused to, and diluted by, theambient air (exterior air).

While this disclosure has been described in connection with what arepresently considered to be useful disclosed embodiments, it is to beunderstood that the disclosure is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. An apparatus for reducing hydrogen concentrationin exhaust gas of an exhaust system of a fuel cell vehicle, theapparatus comprising: a bumper cover disposed at a rear portion of thefuel cell vehicle, the bumper cover forming a streamlined exteriorsurface; and an exhaust gas guiding unit interconnecting the exhaustsystem and the bumper cover, the exhaust gas guiding unit guiding theexhaust gas to the streamlined exterior surface of the bumper cover. 2.The apparatus of claim 1, wherein, while the exhaust gas is guided tothe streamlined exterior surface of the bumper cover, hydrogen in theexhaust gas flows along the streamlined exterior surface of the bumpercover, the hydrogen thereby being diffused to, and diluted by, exteriorair.
 3. The apparatus of claim 2, wherein the exhaust gas guiding unitcomprises an extension portion formed by extending an exhaust end of theexhaust system, the extension portion being connected with a bottom ofthe bumper cover.
 4. An apparatus for reducing hydrogen concentration inexhaust gas of an exhaust system of a fuel cell vehicle, the apparatuscomprising: a bumper cover disposed at a rear portion of a vehicle, thebumper cover forming a closed space connected with an exhaust end of theexhaust system, the bumper cover further forming a streamlined exteriorsurface, the closed space being connected with a rear of the bumpercover by a gap formed along a length direction of the bumper cover; andan air amplifier exhausting the exhaust gas to the streamlined exteriorsurface through the gap, the air amplifier guiding exterior air to thestreamlined exterior surface.
 5. The apparatus of claim 4, wherein theair amplifier guides the exhaust gas to stick to, and flow along, thestreamlined exterior surface of the bumper cover such that hydrogen inthe exhaust gas is diffused to, and diluted by, the exterior air.
 6. Theapparatus of claim 4, wherein: the bumper cover is formed in a shape ofa hollow loop in cross-section; the streamlined curved surface is formedas a rear surface of the bumper cover; and the rear surface isoverlapped by a front surface with the gap at a bottom of the bumpercover.
 7. The apparatus of claim 6, wherein a blocking protrusion isformed at a top of the bumper cover so as to block hydrogen contained inthe exhaust gas from flowing upward.
 8. An apparatus for reducinghydrogen concentration in exhaust gas of an exhaust system of a fuelcell vehicle, the apparatus comprising: a collecting member installed atan interior of a bumper cover, the bumper cover being disposed at a rearportion of the fuel cell vehicle, the collecting member collectingexhaust gas exhausted from the exhaust system, the collecting memberexhausting the collected exhaust gas to the interior of the bumpercover, the bumper cover forming a streamlined exterior surface; and anexhaust portion comprising a mesh screen formed at the bumper cover, theexhaust portion discharging exhaust gas at the interior of the bumpercover to an exterior of the bumper cover, the exhaust portion guidingthe discharged gas to the streamlined exterior surface of the bumpercover.